Extremely strong 13CO J = 3→2 line in the "water fountain" IRAS 16342-3814: Evidence for the hot-bottom burning

Abstract

We observed four "water fountain" sources in the CO J = 3→2 line emission with the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope in 2010-2011. The water fountain sources are evolved stars that form high-velocity collimated jets traced by H2O maser emission. The CO line was detected only from IRAS 16342-3814. The present work confirmed that the 12CO to 13CO line intensity ratio is ∼1.5 at the systemic velocity. We discuss the origins of the very low 12CO-to- 13CO intensity ratio, as possible evidence for "hot-bottom burning" in an oxygen-rich star, and the CO intensity variation in IRAS 16342-3814. © 2012. Astronomical Society of Japan.